The German chemist J. Lothar Meyer attempted to arrange the known elements by noting similarities in physical properties. The Russian chemist Dmitri Mendeleev approached the problem from chemical properties which seemed to repeat when the elements were arranged in a certain pattern.
Today the credit goes to Mendeleev because he went one step beyond a system of classification.
In Mendeleev's original table, the elements were arranged in order of increasing atomic mass, like Dalton's and Newlands'. But unlike these earlier methods and that of his contemporary Meyer, Mendeleev had carefully considered the chemical properties of the elements and had made a daring prediction.